Facile large-scale preparation of vanadium pentoxide -polypyrrole composite for aqueous zinc-ion batteries

Abstract

Aqueous zinc-ion batteries (ZIBs) have been noted as promising large-scale energy storage systems owing to their cost-effective and environmentally friendly merits. However, the further development of ZIBs is limited by suitable cathodes, which normally suffer from the challengers of cathode dissolution, poor electronic conductivity, and low ion diffusion coefficient. Herein, we adopted a simpler, prone largescale preparation strategy of in situ polymerization at room temperature to prepare V2O5-polypyrrole (V2O5-PPy) nanobelt composite that the V2O5 act as an oxidant for pyrrole (Py) polymerization, and Py in situ polymerized on the V2O5. The V2O5-PPy nanobelt composite contributes to preventing the dissolution of vanadium elements, improving electronic conductivity, and forming oxygen vacancies (Vö). As a result, an excellent initial discharge capacity of 441 mAh g−1 at 0.1 A g−1 and 291 mAh g−1 at a high current density of 5 A g−1 was realized. More importantly, a capacity retention rate of 95.92% after the long-term 2000 cycles at a high current density of 5 A g−1 was achieved. The capacitance control is dominant and accounts for 80.76% at 0.5 mV s−1, and the zinc ion diffusion coefficient during the cycle is 4.4 × 10−8-1.62 × 10−9 cm2 S−1, indicating good kinetics. Our work provides a feasible strategy for the large-scale fabrication of V2O5-PPy for ZIBs.